The invention relates to a method and means for assembling shroud segments to successive groups of blades in turbine-rotor stages.
The blades of given stages of a turbine rotor are first assembled to the shaft or hub portion serving the particular stage. The radially outer end of each blade is characterized by a short cylindrical tenon, which projects radially beyond the shoulder at termination of the foil section of the blade. An arcuate shroud segment has preformed apertures for reception of a succession of blade tenons, to define their fixed angular spacing when the tenons have been deformed into locked engagement to the shroud segment. A high-speed turbine rotor must be well balanced and the blade tenons must be properly secured if quality performance and durability are to be realized. Traditionally, this has been an art, exercised by skilled workers with impact-riveting action on successive tenons. Yet, however skilled the worker, it has been well-nigh impossible to achieve total uniformity, so that life and performance have suffered. Careless rivet-tool impact of the shroud segment induces distortion and sets the stage for something less than optimum performance.